نتایج جستجو برای: dimethoxy porphyrins

تعداد نتایج: 6278  

Journal: :Journal of chromatography. B, Analytical technologies in the biomedical and life sciences 2004
Rafael Mateo Gloria Castells Andy J Green Carlo Godoy Carles Cristòfol

Methods developed for porphyrin analysis have low recoveries and/or poor precision for the less polar protoporphyrin IX. We describe a simple method of analysis of porphyrins and biliverdin in bile and excreta of birds based on extraction with HCl 3N: acetonitrile and HPLC/UV analyses. Recoveries were good for protoporphyrin IX and other porphyrins (>79%). Applications of this method showed tha...

Journal: :Brazilian journal of medical and biological research = Revista brasileira de pesquisas medicas e biologicas 1999
S G Afonso R Enríquez de Salamanca A M Batlle

Porphyrias are a family of inherited diseases, each associated with a partial defect in one of the enzymes of the heme biosynthetic pathway. In six of the eight porphyrias described, the main clinical manifestation is skin photosensitivity brought about by the action of light on porphyrins, which are deposited in the upper epidermal layer of the skin. Porphyrins absorb light energy intensively ...

Journal: :Molecules 2015
Ambrish Singh Yuanhua Lin Mumtaz A Quraishi Lukman O Olasunkanmi Omolola E Fayemi Yesudass Sasikumar Baskar Ramaganthan Indra Bahadur Ime B Obot Abolanle S Adekunle Mwadham M Kabanda Eno E Ebenso

The inhibition of the corrosion of N80 steel in 3.5 wt. % NaCl solution saturated with CO2 by four porphyrins, namely 5,10,15,20-tetrakis(4-hydroxyphenyl)-21H,23H-porphyrin (HPTB), 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphyrin (T4PP), 4,4',4″,4‴-(porphyrin-5,10,15,20-tetrayl)tetrakis(benzoic acid) (THP) and 5,10,15,20-tetraphenyl-21H,23H-porphyrin (TPP) was studied using electrochemical impedan...

2013
GAURI D BAJJU NARINDER SINGH

The synthesis and characterization of new meso-substituted and -substituted unsymmetrical metallorphyrins has been described. A new modified Alder method was used for the synthesis of unsymmetrical porphyrins. Reaction of these unsymmetrical porphyrins with metal chlorides and nitrates afforded the corresponding metalloporphyrins in high yields with excellent purity. These porphyrins and their...

2012
Dana Vlascici Eugenia Fagadar-Cosma Iuliana Popa Vlad Chiriac Mayte Gil-Agusti

Three A(3)B porphyrins with mixed carboxy-, phenoxy-, pyridyl-, and dimethoxy-substituent functionalization on the meso-phenyl groups were obtained by multicomponent synthesis, fully characterized and used as ionophores for preparing PVC-based membrane sensors selective to iron(III). The membranes have an ionophore:PVC:plasticizer composition ratio of 1:33:66. Sodium tetraphenylborate was used ...

Journal: :Chemical science 2015
Toru Aoki Hayato Sakai Kei Ohkubo Tomo Sakanoue Taishi Takenobu Shunichi Fukuzumi Taku Hasobe

Charge-transfer (CT) π-complexes are formed between planar porphyrins and 1,4,5,8,9,12-hexaazatriphenylene (HAT) derivatives with large formation constants (e.g., 104 M-1), exhibiting broad CT absorption bands. The unusually large formation constants result from close face-to-face contact between two planar π-planes of porphyrins and HAT derivatives. The redox potentials of porphyrins and HAT d...

Journal: :Clinical chemistry 1967
C R Scott R F Labbe J Nutter

A procedure has been developed for the assay of urinary porphyrins. Total porphyrins are extracted from acidified urine into n-butanol. The fluorescence of this solution under ultraviolet illumination gives a preliminary indication of abnormal levels of porphyrins. They are then separated and identified by thin-layer chromatography. Uroporphyrin and coproporphyrin can be qualitatively estimated...

Journal: :Organic & biomolecular chemistry 2015
Chihiro Maeda Kosuke Kurihara Motoki Masuda Naoki Yoshioka

The synthesis and photophysical properties of cyano and ethynyl substituted carbazole-based porphyrins were investigated. The introduction of ethynyl groups induced red shifts, while that of cyano groups induced blue shifts of their absorption bands, which was supported by MO calculations. Ethylenedioxy-appended porphyrins were also prepared via a coupling reaction. The conjugated and electroni...

2006
B. Frydrych

The aim of this study was to complete research on the porphyrogenic effect of hexabrombenzene (HBB) and tetrabromobisphenol-A (TBBP-A). Experiments were performed on female Wistar rats. The examined compounds were administered in sunflower oil intragastrically in 3 doses. The determination of porphyrins in tissues was carried out by means of high-performance liquid chromatography. Repeated HBB ...

Journal: :Clinical chemistry 1994
N Schoenfeld R Mamet

The second-generation quinolone ofloxacin interferes with the screening test of porphyrins. We observed a 20-fold increase in the porphyrin concentration measured in urine of an ofloxacin-treated patient, compared with drug-free normal urine. Two other fluorinated 4-quinolones tested, norfloxacin and ciprofloxacin, had a less marked effect (a twofold increase), whereas the first-generation quin...

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